Intra-cluster receptor density (IRD): a molecular switch for TNFR1 clusters signaling

Abstract

Tumor Necrosis Factor Receptor 1 (TNFR1) signaling regulates cell fate in inflammation, immune responses, and tumorigenesis. While TNF--mediated TNFR1 pathways are well known, the role of receptor clustering remains unclear. Utilizing homo-FRET using fluorescence anisotropy, we show that intra-cluster receptor density (IRD) governs TNFR1 signaling outcomes. Soluble TNF- (sTNF-) increases IRD at cluster cores but decreases it at rims via receptor reorganization. Reducing IRD through membrane tension, zafirlukast, actin depolymerization, or cholesterol depletion suppresses sTNF- signaling, whereas increasing IRD by lowering membrane tension or exposing cells in a 3D gel-like microenvironment triggers ligand-independent activation. These findings reveal IRD as a key regulator of receptor signaling, with potential relevance across related receptor families and innovative strategies in modulating TNFR1 signaling. TeaserIntra-cluster receptor density (IRD) is critical for TNFR1 signal modulation, with higher IRD activating and lower IRD impairing the TNFR1 signaling.